Automatic fuel injection valve



March 12,1940. FRANK 2,192,884

AUTOMATIC FUEL INJECTION VALVE Filed July 5, 1937 INVENTOR.

BY ATTORNEYS.

' Patented Man 12, 1940 UNITED STATES PATENT, OFFICE nu'rom'no FUELnmzcrron VALVE Horace I. max, Pittsburgh, Pa. Application July 3, 1537,Serial No. 151,902

This invention relates to new and useful improvements in automaticinjection valves for Diesel engines and-the like, and it is among theobjects of the invention to provide a valve which shall be positive inits operation to deliver metered quantities of fuel to the combustionchamber of the engine and to positively discontinue the fuel supply atthe end of the delivery period of the fuel without any so-calleddribbling from 0 the orifice.

;A further object of the invention is to provide a fuel valve of theabove designated character which shall be capable of handling the minutequantities of fuel used at idling speedsof Diesel engines in theirapplication to automobiles and the like.

Still another object of the invention is the provision 01 a fuel valveof plunger form adapted to be seated on the upper face of the valve byme- 2 chanical force and which is displaceable by the pressure of theinlet fuel delivered to the valve, whereby when the fuel supply is cuton, the valve will be subjected to a suction stroke, producing a smallvacuum to thereby prevent dribbling of fuel from the valve orifice.

Still a further object of the invention is to generally eliminate thedifliculties inherent in the so-called conventional type of needlevalve, such as the elimination of wear of the valve seat, the

trapping of grit in the. valve seat, and the trapping of air in thevalve chamber, which cause dribbling and misfiring of the Diesel engine.

These and other objects of the invention will become more apparent froma consideration of the accompanying drawing constituting a part hereofin which like reference characters designate like parts and in which:

Fig. 1 is a vertical cross-sectional view of an automatic fuel valveembodying the principles of this invention; and

Fig. 2 an exploded view of parts of the valve in elevation.

In the drawing, the reference numeral i designates he valve body orhousing having a central be e 2, a counterbore ll, threaded ends 4 and5, an end cap 6 and a nozzle i. A counterbore or valve chamber 8 isprovided at the lower end of the body 6 which communicates with a fuelpassage 9 and an air vent Id. The valve chamber 8 terminates in a secondcounterbore H, which is slightly larger than the central opening 2, butsubstantially smaller than the valve chamber '8. The fuel passage 9extends to a fuel inlet 92 consisting of a threaded nipple which isscrewed in the side of the valve body and which is provided with athreaded portion I3 for connection to a fuel supply line that leads to afuel pump adapted to deliver the fuel in metered quantities, and whichis actuated through connection with the crank shaft of the engine to bein timed relation 6 therewith. The air vent I0 is provided with aclosure l4 and the valve body is provided with a radial flange I5 bymeans of which it is mounted in place on the Diesel engine. Disposedwithin the valve chamber 8 is a 10 cylindrical valve "having aconstricted portion I8 that fits in the small counterbore H, and whichis integrally or otherwise joined to a valve stem 19 that extendsthrough the central bore 2 and the counterbore 3 to above the valve body35 i, the upper portion being provided with a screw thread 20 forreceiving a pair of screw nuts 2i and 22. A coil spring 23 is disposedin the counterbore 3, seating against the shoulder formed by the bottomof the counterbore 2 and having its upper end abutting the screw nut72!. By adjusting the nuts 2! and 22, any desired tension may be appliedto the coil spring 23, whereby the valve body I! is retracted to itsclosed position.

With reference to the main body of the valve i1, it is oi cylindricalshape and is a lap fit in the valve chamber 2, constituting a plunger orpiston in its movements therein. The valve is provided with drilledpassages 2d which communicate with a horizontal passage 25 that in 30the upper position of valve I1 is sealed by the cylindrical wall of thevalve chamber 8, but when the valve i! is depressed, it is exposed toand communicates with a chamber 26, which is known as the fire cupdelivery chamber, the bottom of 3b which is provided with an orifice 21.The operation of the above described fuel valve is briefly as follows:The valve body I! normally rests against the end wall of the valvechamber 8, the constricted portion i8 forming a seal against 40 fluidpassage through the central bore into the upper portion of the valvebody. When pressure of the fuel in the inlet i2 exceeds the tension ofspring 23, it will cause downward movement .of the valve H, whichexposes the passage 25 and 4,5 permits the fuel to flow into the firecup delivery chamber 26, thence through the orifice 21 into thecombustion chamber of the Diesel engine. When the fuel supply isshut-ofi by the delivery pump after a metered quantity has been delivsoered, the spring 23 will snap valve I! back into its closed positionneed the end of valve chamber 8, which will bring passage 25 in sealingrelation with the cylindrical wall of the valve chamber 8. This upwardretraction of valve ll pro- 55 duces 'a slight vacuum in the fire cupdelivery chamber 26 so as to retract any fluid in the orifice 21 andprevent dribbling therefrom into the combustion chamber.

When the nozzle is installed in a Diesel engine, air will be present inthe valve chamber 8, and this may be removed by opening the bleeder llto permit the air to escape. The port it is kept tightly sealed duringthe operatin of the Diesel engine to prevent leakage.

As will be evident from the foregoing description of the invention, theconical or needle shape of the valve does not function in the sealing Iof the valve as that is brought about solely by the cylindrical valvechamber 8 and the complementary-shaped lap-fitted valve il. Thus no gritor foreign matter can interfere with the closing of the valve to causedribbling of the fuel. Neither is the cylindrical type valve subjectedto the wear incident to the seating action of a needle valve, whichbecause of pitting and erosion of the constantly abutting surfaces mustbe frequently renewed by grinding, resulting in leakage and mis-firing.

Because of the removability of the conical cup 7 and the end cap 8, thevalve, spring and other elements are readily accessible for inspectionand replacement.

Although one embodiment of the invention has been herein illustrated anddescribed, it will be evident to those skilled in the art that variousmodifications may be made in the details of construction withoutdeparting from the principles herein set forth.

I claim:

A fuel valve for internal combustion engines comprising a valve bodyhaving fuel inlet and outlet pusages, a cylindrical valve chambercommunicating with said passages, a cylindrical valve forming a sealwith the walls of said chamber. an air vent extending from said valvechamber to the side of the valve body, means for opening said vent, aconical-shaped screw cap constituting the lower end of the valve bodyand forming a fire cup delivery chamber beneath the valve chamber, theoutlet passage extending through the tip of said screw cap. a valve stemextending upwardly through the valve body, an end cap at the upper endof the valve body forming a chamher for the end of a valve stem, coilsprings disposed around the valve stem' abutting at one end against thevalve body and at its other end against adjustable end abutments formedat the top end of the valve stem, a flow e through the valve bodyextending from the upper face of the valve and through the cylindricalwall of the valve, the lower end of the valve being shaped complementaryto the bottom wall of the fire chamber, said valve being operative inresponse to pressure of said spring to normally close to seal the valvechamber against the flow of fuel from the inlet passage, and beingfurther operative to displace'the valve downwardly to cause the flow offuel from the inlet passage through the valve passage into the firechamber.

